This invention relates to a device to fix the position of a cylindrical tank. More particularly, this invention prevents rotation of a cylindrical liquified gas fuel tank about its longitudinal axis and limits longitudinal movement of the tank when the tank is attached to a platform as on an industrial type vehicle, for example.
Industrial type vehicles, such as fork-lift trucks, commonly use a flammable gas such as propane, butane or the like as fuel. The fuel is provided for use in a liquid form under pressure in a cylindrical metal tank and the tank is rigidly mounted to the vehicle.
A portion of the fuel is in a liquid state and another portion in a gaseous state within the cylinder. A manually operated valve is provided on one end of the cylinder to permit transfer of the liquid portion of the fuel from the cylinder to the motor through a hose coupled to the valve. The fuel system is designed to operate at a maximum fuel pressure and to guard against developing an excessive pressure, a pressure relief valve near the fuel transfer valve is provided in the cylinder end.
The fuel cylinder is commonly attached to the vehicle with its longitudinal axis horizontal. When attached in this manner, it is important that the pressure relief valve be oriented in a position that it is exposed internally to the gaseous portion of the cylinder since exposure to the liquid portion will impair the proper functioning of the valve.
Andreasen, U.S. Pat. No. 2,915,799, shows a clamping unit in common usage for horizontal attachment of a liquified gas cylinder to a vehicle. To insure that the pressure relief valve is properly positioned in relation to the gaseous portion of the tank, a pin located outward from one of the clamping units projects upward and is inserted through a hole provided in a sleeve or neck ring portion of the tank which surrounds the fuel transfer valve. The hole in the sleeve is large enough to permit free entry of the pin therein but restricts any appreciable rotation of the cylinder about its longitudinal axis. The pin is disposed in relation to the pressure relief valve so that after engagement with the pin, the valve is exposed to the gaseous portion of the tank. Thus, if the pin is properly engaged in the hole in the sleeve prior to securing the tank to the vehicle with the clamping units, the tank is restrained from rotation and the pressure relief valve is maintained in the proper relationship with the gaseous portion of the tank to insure its proper functioning.
The disadvantage of an anti-rotation device of this kind is that the relatively small diameter pin is fragile in an industrial environment and can be easily bent or broken making it possible to install a fuel cylinder in a manner that the pressure relief valve could be inoperative. It would be desirable, therefore, to provide an anti-rotation device for use with horizontally mounted liquified gas tanks which would insure that a tank is secured in place so that the pressure relief valve is properly oriented and that the tank is rigidly restrained from rotating about its longitudinal axis.